1. Field of the Invention
The present invention relates generally to disk drives, and in, particular to a disk drive including a head stack assembly with insulated wiring extending between an actuator coil and an actuator main body section disposed in a lateral wiring protector extending from the actuator body.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA). The spindle motor includes a spindle motor hub that is rotatably attached to the disk drive base and supports a lowermost one of the disks. The head stack assembly has an actuator assembly having at least one air bearing slider, typically several, for reading and writing data from and to the disk. Each slider includes a transducer head for reading and writing data. The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly is controllably positioned in response to generated servo control signals from the disk controller. In so doing, the attached sliders are controllably moved relative to tracks disposed upon the disk for reading and writing operations.
The head stack assembly includes an actuator assembly, at least one head gimbal assembly, and a flex circuit assembly. A conventional “rotary” or “swing-type” actuator assembly typically includes an actuator having an actuator body. The actuator body is configured to rotate on a pivot assembly between limited positions about an axis of rotation. The actuator body includes a main body section. One or more actuator arms extend from one opposite side of the main body section. A head gimbal assembly is distally attached to each of the actuator arms. A head gimbal assembly includes an air bearing slider that is attached to a suspension with a gimbal. The suspension resiliently supports the air bearing slider above the tracks of the disk during operation of the disk drive facilitating the slider to “fly” above the disk.
A coil is supported by a coil support that extends from an opposite side of the main body section. The coil is configured to interact with one or more permanent magnets to form a voice coil motor. The coil is disposed in electrical communication with the disk controller through a flex circuit assembly. Controlled movement of the head stack assembly is achieved by selectively energizing the coil with the generated servo control signals.
The flex circuit assembly is configured (1) to supply current to the actuator coil from the printed circuit board assembly and (2) to carry signals between the transducer heads and the printed circuit board assembly. The flex circuit assembly includes a flex cable (also referred to as a flex circuit cable or flex circuit), an integrated circuit device, and a cable connector.
The flex cable includes a plurality of conductive traces embedded within the flex cable that terminate at the cable connector which is electrically connected to the printed circuit board assembly. The flex cable further includes a base film and a cover which are typically formed of a polyimide material. The plurality of conductive traces is disposed between the base and cover films. Insulated wiring extends along each actuator arm to each transducer head for transmitting data signals to and from the transducer heads. Such insulated wiring is connected to the flex cable.
In addition, an electrical connection is made between the coil and the conductive traces of the flex cable. This typically takes the form of a short segment that extends along a bottom surface of the actuator body. This electrical connection may take a variety of forms. For example, a section of flex material similar in construction to the flex cable may be used. Such a section would lie flat against the actuator main body section, and secured in place with an adhesive. Such flex material is considered relatively expensive. Alternatively, insulated wiring may be used which is considered to be relatively less expensive. However, because such wiring does not have a comparable flat profile like the flex material, there is a concern that during handing and installation of the actuator the insulated wiring may become dislodged or loosened thereby interfering with the intended electrical connection.
As can be appreciated, there is a need in the art for an improved head stack assembly configuration in comparison to the prior art.